The present invention relates generally to an apparatus for tightening chains placed on vehicle tires and methods for using such an apparatus. In particular, the present invention relates to an apparatus for uniformly tightening the chains for motor vehicle tires and methods for using such an apparatus.
During ice, snow or mud conditions, as well as other reduced traction conditions, chains are often installed on motor vehicle tires and trailers to increase traction. A problem often associated with the chains is that they may have a lot of slack and may be quite loose after they are installed. Examples of known devices for increasing the tension on such chains are described, for example, in U.S. Pat. Nos. 4,173,244, 4185,674, 4,237,951, 4,266,593, 4,392,521, 4,679,608, 4,799,522, 5,284,196, 5,785,783, 5,804,001, 6,026,876, and 6,085,816, the disclosures of which are incorporated herein by reference. Many of these chain-tightening devices are extremely complex and difficult to use.
The non-uniformity of the tightening mechanism of other chain tighteners causes many problems. One such problem is chain roll. Chain roll occurs when loose portions of the chain bunch up and create their own rolling action. Such rolling action can lead to gouging and damaging of the tires, requiring the tires to be replaced.
Also, the non-uniformity of the tightening mechanism can lead to chains that are installed too loosely. Many of the known chain tighteners are unable to keep the chain tight during operation, allowing the chain to work loose or shift off-center. In either instance, the loosened or off-center chain can fly up and damage to the vehicle.
The present invention includes an apparatus for tightening chains that are installed on a tire, as well as methods for using such an apparatus. The chain-tightening apparatus provides a mechanism for uniformly tightening the chains, as well as keeping a uniform tension on the chains while the tire rotates. The apparatus attaches to the chains quickly and easily, making the method of tightening such chains simple.
The present invention comprises a system for tightening a tire chain or like antiskid devise upon a tire. The system comprises a plurality of attachments or hooks for attaching the apparatus to chain links or other suitable attachment points located at radially spaced intervals on the chain. A flexible connector or cable in the form of a closed loop is movably connected to the hooks. An apparatus for taking up slack, such as a reel with a winding inner cylinder, is used to take up slack in the cable and put the cable under tension. When the cable is tensioned there is an essentially constant tension around the loop of the cable imparting at each of the hooks a chain-tightening center-directed radial force. The reel can be locked to main maintain the cable in a tensioned state. When it is desired to remove the apparatus, the lock is released to release the tension on the cable.
The attachment points are radially spaced, which means they are located around a central point, preferably symmetrically and essentially equally spaced. Prefect symmetry and spacing is not required, but spacing should be such that the chain is held in on the tire. It is an essentially symmetrical center-directed force that effectively holds the chain on the tire, and any asymmetry in the attachment of the apparatus of the invention should not significantly compromise the uniformity of the holding force on the chain.